Agriculture Reference
In-Depth Information
(e.g. exposure, safe upper levels of nutrients)
are similar to those assessed for the human
nutritional impact of crops with nutritionally
improved characteristics, as considered by a
dedicated annex of the Codex Alimentarius
guideline (Codex Alimentarius, 2008; see
also Chapters 5-7).
which it then needs to be determined if and
which further tests need to be performed.
Using these omics techniques, various
studies have been carried out in which GM
crops were compared with their conventional
non-GM counterparts. Several recent
reviews highlight the i ndings that come out
of such studies applying metabolomics as
well as other omics techniques to GM crops.
Davies
et al
. (2010), for example, reviewed a
number of omics studies in maize, rice and
potato, as well as some soft fruits, including
studies that were carried out with various
genotypes, in multiple locations and during
more than one season. In many cases, the
impact of environment and genotype was
found to be substantial, while that of genetic
modii cation appeared to be relatively
minor.
In line with this i nding by Davies
et al
.
(2010) are the outcomes of a comprehensive
review of the published literature on GMO
safety, including studies on omics research
on GM crops, by Ricroch (2013). With regard
to the omics on crops with agronomic traits
but without intended alteration of intrinsic
crop metabolism, this author identii ed 36
studies on various cereals (barley, wheat,
maize, rice) and non-cereals (cabbage, pea,
potato, soybean). It was concluded that
environmental factors had a greater impact
than genetic modii cation, that there were
also fewer impacts of it in comparison with
conventional breeding techniques and that
these outcomes did not raise concerns over
the safety of commercialized GM crops (see
Chapter 8).
In order to prepare for the advent of future
GM crops with more complicated
modii cations, which in turn may increase
the likelihood of unintended ef ects, it has
been suggested that advanced 'omics'
techniques be developed and applied. h e
latter are holistic, non-targeted analytical
techniques that can monitor the crop
for changes in its constituents at dif erent
levels of cellular organization: including
transcriptomics being used for measuring
the levels of 'messenger' RNA (mRNA)
indicative of gene expression activity;
proteomics, measuring the diversity of
expressed proteins; and metabolomics,
analysing the diversity of chemical com-
pounds (metabolites). Commonly used
techniques include cDNA microarrays for
transcriptomics (increasingly being replaced
by next-generation sequencing (NGS)
analysis); two-dimensional protein electro-
phoresis for proteomics (increasingly being
replaced by mass spectrometry (MS) analysis
of peptide structures); and nuclear magnetic
resonance or gas or liquid chromatography
coupled to mass spectrometry for metab-
olomics. A more detailed review of these
dif erent techniques and their potential
application in GM crop safety assessment is
provided by Kok
et al
. (2010). h ese authors
also note that before omics can become
mainstream in the risk assessment pro-
cedure, they should be standardized and
validated, while databases also should be
established to provide background data on
the variability of the components measured
under natural conditions in non-GM
varieties of the specii c crops. h e outcomes
should then help to identify dif erences,
particularly those that are outside the
boundaries of background variability, for
A well-developed framework has been
established for the regulatory pre-market
safety assessment of GMOs based on
international consensus as enshrined in the
guideline of Codex Alimentarius (2008).
While this guideline pertains to food, it
also applies well to the safety assessment
of animal feed. Central to the harmonized
approach devised by the guideline is
the comparative assessment, which
entails a comparison of the compositional
